Pobatioh of



W. C. BRINTON, JR.

PROCESS OF MAKING ELECTRICAL CONDENSERS.

APPLICATION FILED JULY 20.1911.

L8Q7MD Patent-ed June 24, 1919.

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MAKE/V70? Makin WILLIAM BRIN'ION', m, 0! KENNETH SQUARE, PENNSYLVANIA,ABSIGNOR T0 PHILIPS-BENTON COMPANY, OF KENNETT SQU, TENNSYLV W3 POBATION0F PENN SYLV 1. r i

IPROCESS OF MAKING ELECTRICAL CONDENS Specification of Letters Patent.Patented Junta Tll.

Application filed July 20, E917. Serial no. muss.

C. BRINTON, Jr., a citizen of the United States, residing at KennettSquare, county of Chester, and State of Pennsylvania, have invented anew and useful Improvement in, Processes of Electrical Condensers, of Vwhich the fol owing is a full, clear, and exact description, referencebeing had tothe accompanying-qlrawings, which form a part of thisspecification.

The object of my invention is to provide a new and simple process formaking electrical condensers, which will be extremely economical, and atthe same time produce condensers of uniform and maximum efficiency.

One of the most serious difliculties in the manufacture of condensers isthe effectual elimination and permanent exclusion ofmoisture. In theprocess of manufacture, as ordinarily carried on, the paper or other d1-electric material to be embodied in the condenser is thoroughly dried toexpel the nor- 'mally contained moisture. The layers of dielectricmaterial and conducting material are then arranged in a pile or woundinto a spiral and, by prolonged boiling, are impregnated with wax, oliveoil, or other di electric material. The layers are then con-:- solidatedby pressure. A casing is usually applied to the condenser afterconsolidation, although it may be applied before, as in the patentissued to me August 14, 19171, No. 1,237,015. This process involvesconsiderable labor and expense. The drying and impregnating stepsrequire some hours of time. The compressing operation, involving theexpulsion of wax in the die, isuuncleanly and involves danger ofburningvof the operative. The process must be continuous, to preventreabsorption by the paper of moisture and cooling ofthe impregnating waxbefore compression. The complete expulsion of moisture is impossible,while in rrost (ondensers the interstices in the final product are notso efiectually closed as to prevent the entrance of moisture, so thatthe condenser is apt to be relatively shortlived. The preliminary dryingof the paper materially weakens its strength and the leads are apt tocut into ,the paper in the compressing operation.

A large proportion of the condensers, after completion, are found to betoo ineflious factor.

Specifically my object is to overcome all these difliculties andeliminate all these ob-' jections. I entirely avoid the preliminarydrying of the paper, reduce the period of impregnation from hours tominutes, enable the compression of the layers to be conducted inacleanly'manner and with relatively small application of power, avoidthe necessity of carrying on the different steps paper, preferably notpreliminarily dried,

and aluminum foil) in a pile of long strips, position the leads, windthe strip on a mandrel into a cylindrical shape, withdraw thecylindrical condenser body, insert it into a tubular casing of drawnsteel, and, without inttrmcdiate treatment, subject the whole to'pressure to convert the cylindrical incased condenser into a condenserof oblong shape in cross section and of considerably reduced volume,thereb consolidating the layers of the condenser ody and pressing thelatter into intimate contact with its casing. The condenser is thenimmersed in a body of dielectric impregnating liquid, such as wax orolive oil, preferably heated; wax,'or similar cient for use, and wasteis therefore a seri- Gill material, being necessarily heated to maintain it fluid. Simultaneously an electric alternating current is passedthrough the condenser. This results in the conversion of the containedwater into steam at a high pressure, the escape of the steam, and thereplacement of the displaced water by the impregnating dielectricliquid.

In describing my process more in detail, I shall refer to theaccompanying drawings, wherein- Figure 1 is a plan view of the apparatusemployed in making the original cylindrical condenser body and also aplan view of the strips of foil and paper before they are wound. Fig. 2is a cross-section through Fig. 1.

Fig. 3 is a side view of the uncovered spirally wound condenser body.

Fig. 4 is an end view of Fig. 3.

Fig. 5 is a side view of the condenser body inserted in its casing. I

Fig. 6 is an end view of Fig. 5. Fig. 7 is .a cross-sectional view ofthe die, with the condenser in place before compress1on.

Fig-8 is a perspective view of the mechanically-completed condenser.

Fig. 9 is a diagram of the moisture-expelling anddielectric-impregnating apparatus.

It will be understood that the specific process about to be described ismerely preferable, and that it involves steps some of which are insubstance known in the art. Further, the ultimate structure of thecondenser, aside from the more complete exclusion of moisture and airand its morecomplete impregnation with dielectric liquid, issubstantially the same as that disclosed in my prior applicationhereinbefore mentioned. v

I first lay, in a suitable trough f, as shown in Figs. 1 and 2,alternate layers of aluminum foil a and paper b. Each layer of paper ispreferably composed of two separate sheets or strips. The paper extendsentirely. across the trough, while the foil strips are of narrowerwidth, alternate foil strips being flush with opposite longitudinaledges of the paper, in' the known manner. Leads 0 are insented betweenadjacent layers of paper and foil as the latter are built up, theseleads being lL-shaped to adapt their projecting ends to the side wallsof the trough. Preferably the paper at one end projects beyond the foiland is wrapped around a mandrel 9 after the building-up operation iscompleted. The mandrel is then rotatedfwidening the foil and paperspirally thereon, the resultant condenser body being shown in Figs. 3and 4:. The mandrel is then withdrawn.

Within the hollow center of the condenser body js-inserted a spirallywound strip of ing, which itself is in intimate contact with theperiphery of the condenser body. The leads of the condenser areconnected to an electric circuit 71 (in which is placed a lamp j inseries with the condenser) and im mersed in a bath is of wax, olive oilor other impregnating dielectric substance. See Fig.

. 9, The current should be an alternating one. If wax is used it shouldbe heated at least to the temperature required to make it highly fluid.I prefer to heat it to a temperature of from 250 to-300 degreesFahrenheit. If an impregnating substance, such as olive oil, is usedwhich is fluid at ordinary temperatures, its artificial heating is notimperative but is desirable.

perature of the impregnating bath. Thus,

.with wax heated to the temperature above mentioned, I have successfullyused a 110 volt 60 cycle circuit, which should be an alternatingone. r

As soon as the condenser, so placed in the electric circuit, is immersedin the bath, the circuit is closed. Thereis suflieient moisture in thepaper to generate a considerable volume of vapor, which acts as a goodconductor, the result being that a gradually in.- creasing quantity ofcurrent leaks through the condenser, as is evidenced by the fact thatthe lamp in the circuit, shortly after immersion, begins to faintlyglow, the light increasing in intensity, until, after the lapse of aminute or so, it glows with a brightness not so far below that which isexhibited it the resistance of the condenser should be entirel cut out.At this time the generation of vapor is at its maximum and the wax hasscarcely begun to permeate the interstices of the condenser. The lampgives its maximum light for but a fraction of a minute and then thelight diminishes, at first slowly and then very rapidly. This indicatesthat the wax has entered the body of the condenser. replacing thedisplaced moisture and vastly reducing the conductivity of thecondenser. The wax apparently penetrates not only any fine intersticesbetween the paper and foil, but also the pores of the paper, renderingit completely dielectric. The time elapsing between the first glow ofthe lampand its final dying out is about two minutes or so. Thecondenser has not yet, however, been the continual boiling at the endsof the condenser. The operation 1s therefore con- The strength of y theelectric current may vary with the temperfectly impregnated, as isevidenced by tinued until all boiling practically ceases.

This may not be until after the lapse of (say) ten minutes.

It is probable that the pressure of steam Within the condenser, duringthe conversion thereinto ofthe water, is close to 100 pounds to thesquare inch, this high pressure insuring complete conversion andexpulsion of moisture and, as a result, complete impregnation with wax.After the removal of the condenser from the bath, its exposed ends arecoated with shellac or other protective covering.

The presence of the lamp in the circuit is advisable in that its actionindicates to the operative that the operation is proceedingsuccessfully; and indeed it is found that it dispenses with thenecessity of any subsequent testing. Such testing of completedcondensers has heretofore been imperative, because, notwithstanding theexercise of great care in their manufacture, the proportion ofinefficient condensers, produced by ordinary processes, is very large.Con densers made by my process, however, when tested in the usual way,not only exhibit maximum efiiciency, but also uniform efficiency, thepercentage of inefiicient condensers being zero.

It is obvious .that with the great saving of labor and time achieved bythe use of my process, and withthe elimination of the serious factor ofwaste arising from the rejection'of inefficient condensers,.the use ofmy process is highly economical. Further, owing to the completeexpulsion of moisture, the reduction toa minimum of the intersticeswithin the condenser body, the complete impregnation of any intersticesthat exist and of the pores of the paper, the resultant permanentexclusion of moisture,

, and the fact that the condenser will not bleed or sweat at hightemperature, the life of the condenser is greatly prolonged.

Whilethe specific process herein described isthe best way now known tome of practising my improved process, I have succeeded in makingcondensers of a somewhat inferior, but yet of a very high, grade, bytaking the incased and compressed condenser and passing through it,without immersing it in an impregnating material, an alternating 110volt 60 cycle current for a period of about fourteen minutes with thelamp in circuit as described, and then dipping the ends in shellac. Theobserved phenomena, however, diifered from that above described in thatthe lamp glowed brightly for a period of approximately ten minutes.

An operative. and efficient condenser can also be made if thepreferredprocess is modified by omitting the preliminary compression andcondensation of the layers of dielece trio and conducting material,Whether the condenser is or is not incased.

till;

The success of the process seems to be attributable to the fact that theelectric current produces an'internal heat which is sulficient inintensity'to convert all the moisture into vapor within a much shorterperiod of time than is possible if reliance be had solely upon the heatimparted to the impregnating material, the temperature beingsufficiently high to carbonize-and therefore functionally destroy-thedielectric material if such temperature were maintained a substantiallength of time. Thus, if reliance be placed solely on the heat impartedto the impregnating material, and such material be heated. up to atemperature corresponding to that which is produced internally by theelectric current, the paper will char before the moisleakage of currentthrough the condenser necessarily ceases, the internal temperaturedropping to the temperature of the impregnating material. i

It will be understood that while the presence of a lamp in circuit isunnecessary to the execution of the process, the voltage issubstantially reduced by the presence of the lamp, and if the lamp iscut out of the circuit, great care is required in carrying on theprocess. Indeed, it may be questioned whether the carrying out of theprocess, without some resistance in circuit, would not be attended withserious difliculty, as the presence of such resistance prevents internaloverheating, the result of which would be the burning of the dielectriclayers.

While in the above description I have explained the operation'of theprocess on the theory that the contained moisture is converted intovapor during the passage of the electric current, it is quite possible,if not probable, that-what actually occurs is an electrolytic action,whereby the moisture and air contained in the condenser body is ionized,that is, converted into its original elements. The precise theory bywhich to account for the results secured, is, however, of littleimportance, the fact being that the finished condenser has in thehighest degree the qualities attributed to it and that the reciteddifliculties of manufacture are en--- tirely overcome.

' Having now fully described my invention,

what I desire to claim and protect by Letters Patent is:

1. The process of making electrical conthe condenser body an electriccurrent of a strength sufiicient to raise the internal temperature ofthe condenser to the point required to expel the moisture withoutdestruction of the dielectric material.

2. The process of making electrical condensers which consists inarranging layers of conducting and dielectric material to form acondenser body, and then passing throu h the condenser 'body an electriccurrent or a strength suflicient to effect the expulsion of containedmoisture, thereby facilitating the passage of current therethrough, andinterposing a resistance in the circuit to limit the passage of current,and consequently the internal temperature, until the conductivity oftill the condenser is substantially reduced by the expulsion ofmoisture.

3. The process of making electrical condensers which consists inarranging layers of conducting and dielectric material to form acondenser body, and immersing the same in an impregnating dielectricsubstance in aliquid condition and while the same, is so immersedpassing through the condenser an electric current, thereby expelling thecontained moisture and causing the dielectric substance to permeate theinterstices of the condenser.

4. The process of making electrical condensers which consists inarranging layers of conducting and dielectric material to form acondenser body, and immersing the same in an impregnatlng dielectricsubstance in a heated and liquid condition and while the same is soimmersed passing through the condenser an electric current.

5. The process of making electrical condensers which consists inarranging layers of conducting and dielectric material to fornr denserswhich consists in arranging layers of conducting and dielectric materialto form a condenser body, and immersing the same in an impregnatingdielectric substance in a liquid condition under atmospheric pressure,and while the .same is so immersed passing through the condenser anelectric current.

7. The process of making electrical condensers which consists in firstconsolidating by pressure layers of conducting and dielectrio materialto form the condenser body, and. then passing through the condenser bodyan electric current of a strength suficient to expel the containedmoisture and raise the internal temperature'of the condenser to thepoint required to so expel the moisture Without destruction of thedielectric material.

8. The process of making e ectrical con-.

densers which consists in consolidating layers of conducting anddielectric material to form a compressed condenser body, immersing thecondenser body in an impregnating dielectric substance in a liquidcondition, and while the same is so immersed passing through thecondenser an eleotriccurrent.

9. The process of making incased electrical condensers which consists inarranging layers of conducting material anddielectric material to formthe condenser body, applymoisture without destruction of the dielectricmaterial.

10. The process of making incased electrical condensers which consistsin arranging layers of conducting material and dielectric material toform the condenser body, applying thereto a casing of deformablematerial conforming in shape to the condenser body, subjecting thecasing to pressure to effect a substantial reduction in its volume,thereb consolidating the layers and pressing t e casing and its contentsclosely together, immersing the incased compressed condenser in animpregnating dielectric substance in a liquid condition and while thesame, is so immersed passing through the condenser an electric current.

11. The process of making incased electrical condensers which consistsin arrang-' ing layers of conducting and dielectric material and windingthem in circular form to form a cylindrical condenser body, applyingthereto a cylindrical casing of deformable material, subjecting thecasing to pressure along radial lines to convert the cylindricalcondenser into a polygonal condenser having a substantially decreasedvolume, immersing the incased compressed condenser in an impregnatingdielectric substance in a liquid condition and while the same is soimmersed passing through the condenser an electric current.

12. The process of making in cased electrical condensers which consistsin arrangin layers of conducting material and dielectric material toform the condenser body, applying thereto a casing of deformablematerial conforming in shape to the condenser moisture by a dielectricimpregnating substance in a liquid condition.

'In testimony of which invention have 10 hereunto set my hand, atPhiladelphia, Pa, on this 16th day of July, 1917.

WILLIAM G. BRINTQN, JR.

